Never do two DD back to back that is the worst option! UD are not supposed to be moderate they are meant to fuel your next DD. your best option is number one. Keep your DD normal and just nibble at the event and try to stay within your calorie as much as possible.

Reagan, it makes me laugh when I respond to these questions because I never change my rotation. Too complicated for me, I think.
But, what I hear is that you don't follow a MD with a DD. it's too much restriction. Somebody else will chime in before long. All the best with it.

Ideally you would fast until the event, then eat your DD calories at the event.

That's not always doable, or you need to change your rotation for whatever reason. In that case, the best option would be to do your normal DD, follow that with a MD (average your calories for UD/DD), then have the event now fall on an UD. Think small, medium, large if that helps. Now your rotations are changed and you can resume the day after the event with a DD.

If you don't have time to insert a MD, you could make your DD into a MD and have your normal UD the next day.

JUDDD is very flexible. It's really however YOU want to handle it. Some people use MDs every week with no problems. Others do stall or slow down if they use them. You won't know how it works for you until you try it.